President Park Geun-hye, in a nationally televised parliamentary address defending her decision to shut down a jointly run factory park in North Korea, said South Korea will take unspecified "stronger and more effective" measures to make North Korea realize its nuclear ambitions will result only in speeding up of its "regime collapse."

Park shut the park in response to the North's recent long-range rocket test, which Seoul and Washington see as a test of banned ballistic missile technology. North Korea last month also conducted a nuclear test.

Both developments put the country further along it its quest for a nuclear armed missile that could reach the US mainland.

Without elaborating, Park said the North has diverted Seoul payments to North Korean workers at the factory park to the Pyongyang leadership, which is in charge of nuclear and missile development.

She also said the South has sent more than USD 3 billion in government and civilian aid to the North since mid-1990s.

Park called for support for her government amid a divide in South Korea about its tough response to North Korea.

Park's speech contained harsh language, describing North Korea as "merciless" and under an "extreme reign of terror" following recent purges of top officials that outside analysts say were aimed at bolstering leader Kim Jong Un's grip on power.